Idle talk, chatter.
1857. Whenever he presents himself in the presence of the Saints, and attempts to entertain them or amuse them with his chin-music, they expect that he will say something funny.George A. Smith at the Bowery, Salt Lake City, Aug. 2: Journal of Discourses, v. 101.
1872. The thing Im on now is to roust out somebody to jerk a little chin-music for us and waltz him through handsome.Mark Twain, Roughing It, ch. vi. (N.E.D.)